Design Of Electric Valve Localizer Based On Direct Torque Control

The electric valve localizer is designed by use of direct torque control as thescheme of motor control does not need complex calculation for coordinatetransformation, possesses simplicity, reliability and good dynamic response and canimprove the speed and accuracy of localizing of electric valve, which may enhancethe dynamical and the steady-state performances of process control system in manyapplications.After an overview, present situation and development trend of the electricvalve at home and abroad, the structure of the electric valve is introduced. Thevalve location is controlled accurately by location and speed feedback after thelocalizer receives valve location single on the spot or remote. The function ofmotor protection, shifting from manual to automatic, communication, keyboardentry and LCD display make the valve work more accurate and operate moreconvenient.In the thesis, two principles of direct torque control, hexagonal flux linkagetorque direct self-control and roughly spherical flux linkage direct torque controlare respectively introduced. Then the two direct torque control system are modeledand simulated by use of MATLAB. The performance characteristics of the twocontrol systems and application are compared according to the simulation results.And then the roughly spherical flux linkage direct torque control is determined touse in the electric valve servo control system. Base on the abovementioned, thecircuit of the electric valve localizer is designed with the core of Microchip’s motorcontrol chip dsPIC33FJ28MC506A. The design of hardware circuit and the keyflow of software are presented.